I am able to try Marketo Rest API for Opportunity http://developers.marketo.com/documentation/opportunity-api/
but i am not able to view this in the Marketo User Interface. I am able to find lead database where all my leads created exist. But couldnt find where my created opportunities go and sit.
Opps are read only and can only be viewed on a lead by lead basis by clicking on individual lead records to view the Opp tab.